In dental field, it is important to obtain a teeth image during the course of treatment. An intra-oral camera can provide a convenience for directly imaging the teeth in the cavity environment, and it is widely used in hospitals.
However, since surfaces of teeth are very smooth and translucent, and covered with saliva, it is very easy to capture some specular reflection brought from the smooth surface. For both auto-exposure and fixed-exposure, the specular reflection would always result in some over-saturation highlight regions in the images, which greatly damages the details of the images and makes the images displayed ultimately very unclear for density. In certain dental practice, such as the examination of some amalgam areas and moisture tooth smooth surface, the over-saturated highlight regions make it impossible to make any diagnosis on lesions in reflection region and make visual observations very difficult.
More importantly, the over-saturated specular highlight regions caused by the specular reflection make any computer-based automatic lesions detection system fail in the regions, which will be regarded as false positive or false negative.
Although technology of HDR imaging has been widely used in the field of image processing, it is rarely applied to the field of 2D intra-oral imaging. Moreover, in certain cases, even if the intra-oral imaging technical solution adopting the technology of HDR, it can't suppress the aforesaid specular reflection and remove the over-saturated highlight area.
It would, therefore, be desirable to provide a method which remove the specular reflection such that highly clear images of teeth can be presented.